如何為記錄類數據對象的枚舉屬性設置默認值？

Question

recordclass dataobjects 可以很好地處理枚舉屬性，除非你需要設置一個默認值，這會導致SyntaxError （從 0.17.5 版本開始）：

In [1]: from enum import Enum, auto

In [2]: from recordclass import dataobject

In [3]: class Color(Enum):
   ...:     RED = auto()
   ...: 

In [4]: class Point(dataobject):
   ...:     x: float
   ...:     y: float
   ...:     color: Color
   ...: 

In [5]: pt = Point(1, 2, Color.RED)

In [6]: pt
Out[6]: Point(x=1, y=2, color=<Color.RED: 1>)

In [7]: class Point(dataobject):
   ...:     x: float
   ...:     y: float
   ...:     color: Color = Color.RED
   ...: 
   ...: 
Traceback (most recent call last):
...
  File "<string>", line 2
    def __new__(_cls_, x, y, color=<Color.RED: 1>):
                                   ^
SyntaxError: invalid syntax

這個問題有解決方法嗎？

Answer 1

假設問題中的示例是准確的，您需要覆蓋標准和Enum.__repr__() ：

class Color(Enum):
    #
    def __repr__(self):
        return f'{self.__class__.__name__}.{self._name_}'
    #
    RED = auto()

Answer 2

從 0.18 開始，可以使用任何類型的默認值。

from recordclass import dataobject
from enum import Enum, auto

class Color(Enum):
    RED = auto()

class Point(dataobject):
    x: float
    y: float
    color: Color = Color.RED

>>> pt = Point(1,2)
>>> pt
Point(x=1, y=2, color=<Color.RED: 1>)
>>> pt.color
<Color.RED: 1>
>>> type(pt.color)
<enum 'Color'>